Vehicle tire intended to be fitted with spikes

ABSTRACT

The tire (10) has asymmetric or inhomogeneous regions (14 g) which are disposed to produce a force component turning the fixed spike, respectively the sleeve-mounted spike (15) so that the fixed spike, respectively the sleeve-mounted spike (15), is arranged at first contact with the road surface (13) to meet the road surface (13) substantially in perpendicular position.

BACKGROUND OF THE INVENTION

The present invention concerns a vehicle tire intended to be fitted withspikes.

Increasing traffic load and spike tyres in combination have proven to bea remarkable road attrition factor. In some countries this has even ledto prohibition of spike tyres, or at least to considerable restrictions.

In Nordic conditions, the beneficial effect of anti-slip means on thesafety and flexibility of traffic has on the other hand been irrefutablydemonstrated, and this effect should not be sacrificed; instead, theassociated drawbacks should be eliminated. Good results will be achievedby further developing both the road superstructures and the anti-sliptires.

As a pneumatic automobile tyre rolls on an even surface, it isconsiderably flattened radially, owing to its flexibility, whereby inthe contact region longitudinal as well as transverse forces aregenerated owing to changes of the rolling radius.

The longitudinal forces acting on the spike when the tire is rolling aredue to bending of the body structure, to longitudinal slipping and tothe stress wave building up in the rubber.

When a spike approaches the point of contact with the road, the tyrebody undergoes bending such that the radius of the bent part issignificantly smaller than that of equivalent parts of the load-freetyre. This deflects the spike, which has been mounted at right anglesagainst the surface, to assume a vertical position before contact withthe road. Owing to the protrusion of the spike point, however, the spikeis not turned sufficiently; it meets the road surface in an obliqueposition. At this stage, the forces due to slipping tendency also beingto exert their influence.

Traditionally, the shape of the spike has been symmetric and it has beenmounted in a hole, perpendicular against the wear surface of the tire,whereby it meets the road in a slightly oblique position, as describedabove. The oblique contact of the spike with the road, as well as itsbeing pushed deeper into the tyre in oblique position during the initialpart of road contact, cause damage to the rubber and to the spike whichimpairs the friction properties of the spike, detracts from thedurability of the spike and increases its road attrition properties.

SUMMARY OF THE INVENTION

The aim of the invention is to achieve an improvement in currently knownvehicle tire designs intended to be fitted with spikes. The morespecific aim of the invention is to provide a vehicle tire intended tobe fitted with spikes which may be fitted with fixed spikes,respectively with sleeve-mounted spikes, and in which the drawbackstroubling designs of prior art have been avoided.

The aims of the invention are achieved by means of a vehicle tireintended to be fitted with spikes which is mainly characterized in thatthe tire comprises asymmetric or inhomogeneous regions which have beendisposed to produce a force component tending to turn the fixed spike orthe sleeve-mounted spike, fitted on the tire in such manner that thefixed spike or the sleeve-mounted spike, is arranged at first contactwith the road surface to meet the road surface in a substantiallyperpendicular position.

Other characteristic features of the vehicle tire of the invention arepresented below.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described more in detail by referring to certainadvantageous embodiments of the invention, presented in the accompanyingdrawings and to which the invention is not meant to be exclusivelyconfined. In the drawings;

FIG. 1 is schematic illustration presenting the force component turningthe spike, the force component lifting the spike and the resultant ofthe road contact force;

FIG. 2 illustrates an advantageous embodiment of the vehicle tireintended to be fitted with spikes of the invention, in schematicsectional projection;

FIGS. 3a and 3b illustrate another advantageous embodiment of thevehicle tyre intended to be fitted with spikes of the invention, inschematic sectional projection and in elevational view respectively;

FIG. 4 illustrates a third advantageous embodiment of the vehicle tireintended to be fitted with spikes of the invention, viewed from thedirection of the plane of the wear surface;

FIG. 5 illustrates a fourth advantageous embodiment of the vehicle tireintended to be fitted with spikes of the invention, viewed from thedirection of the plane of the wear surface;

FIG. 6 illustrates a fifth advantageous embodiment of the vehicle tireintended to be fitted with spikes of the invention, in schematicsectional projection;

FIG. 7 illustrates a sixth advantageous embodiment of the vehicle tireintended to be fitted with spikes of the invention, in schematicsectional projection;

FIG. 8 illustrates a seventh advantageous embodiment of the vehicle tireintended to be fitted with spikes of the invention, in schematicsectional projection and

FIG. 9 presents an eigth advantageous embodiment of the vehicle tireintended to be fitted with spikes of the invention, in schematicsectional projection.

DESCRIPTION OF THE INVENTION

As illustrated in FIG. 1, in a static situation and at low speeds, thepressure effect originating in the contact angle K of the rubber isuniform and its resultant R_(O) is very close to vertical. The rearmargin of the rubber piece 12 bulges out rearwardly and the contactsurface, forwardly against the road. As the speed increases, thepressure pattern becomes more pronouncedly oval. The pressure resultantis also turned forwardly because in the region D the pressure in therubber is lower since no compressive force is present there. Owing torotation of the tire 10 and compression of the rubber 11, the pressureresultant also moves forward to the point R₂ encountering the flange 22of the spike 20, and imparts to it an upward acceleration, with thecomponent F₁, at the same time turning it from the position as installedto a position more nearly perpendicular against the road surface 13,with the component F₂. The spike 20 is enabled to turn since there is nocompression on the front side thereof. By the mode of installing thespike 20, and by its shape, the utilization of the forces mentioned canbe influenced. In FIG. 1, for spike 20 is used a fixed spike 20, its tipbeing indicated by reference numeral 23.

The rubber 11 of the tyre 10 is asymmetrically shaped. Morespecifically, the asymmetric shaping of the tyre 10 may be accomplishedin accordance with the following FIGS. 2-5 below.

In the embodiment of FIG. 2, the vehicle tire intended to be fitted withspikes of the invention in general is indicated by reference numeral 10.The tire rubber is indicated by reference numeral 11 and the wearsurface, by reference numeral 12. The road surface is indicated byreference numeral 13. In this embodiment a sleeve-mounted spike, ingeneral indicated by reference numeral 15, has been installed in thetire rubber 11. The sleeve-mounted spike 15 comprises the rivet 16, therivet head 17, the tip 18 and the sleeve 19.

As taught by the basic idea of the invention, in this embodimenteminences 14 have been provided on the wear surface 12 of the tire 10.Only one such eminence 14 has been depicted in FIG. 2, but it isunderstood that the entire wear surface 12 of the tire is provided withsimilar eminences 14, the wear surface of every sleevemounted spike 15being similar in kind.

In the embodiment depicted in FIGS. 3a and 3b, the wear surface 12 hasbeen shaped to be an intended pattern element 14a. In this embodiment,fixed spikes 20 are used, comprising a body part 21, a flange 22 and atip 23. The other reference numerals are equivalent to those in FIG. 2.

In the embodiment of FIG. 4, the wear surface 12 is shaped to presentknob patterns 14b.

In the embodiment of FIG. 5, the wear surface 12 comprises longitudinalconfigurations 14c. In other words, the asymmetric shaping may beaccomplished by forming on the wear surface 12, tyre-shaped portions 14crunning substantially in the longitudinal direction of the wear surface12.

The properties of the rubber 11 of the tyre 10 may also be changed bytreating the rubber 11 of the tyre 10.

In the embodiment of FIG. 6, the rubber 11 is hardened in the regionindicated by reference numeral 14d, with the aid of heat, radiation,chemicals, etc., so that a region 14d, harder than the rest of therubber material, leads from the contact angle of the pattern element 12to the hole of the sleeve-mounted spike 15, or naturally similarly tothe hole of a fixed spike 20, and which by mediation of the impact fromthe road surface 13 delivers, immediately before the moment of roadcontact, a turning and lifting force component to the sleeve-mountedspike 15 or to the fixed spike 20. In other words, a region 14d harderthan the rest of the rubber material of the tyre is produced at the holefor the sleeve-mounted spike 15 or for the fixed spike 20. Saidhardening may be accomplished in the manufacturing step of the tire 10or thereafter, or not until in conjunction with spike installation, e.g.by age-hardening the rubber material 11 with a rotating drill and byinjecting curable vulcanizing material into the hole.

The embodiment of FIG. 7 is the same as that of FIG. 6 in otherrespects, except that in the embodiment of FIG. 7 one entire half of thepattern element 12, that is, the region 14e, has been hardened in orderto produce a pressure effect, and a fixed spike 20 is used. In otherwords, half of the wear surface 12 of the tyre 10 which is on one sideof the sleeve-mounted spike 15 or the fixed spike 20, has been hardenedover the entire region 14e for directing a pressure effect on thesleeve-mounted spike 15 or on the fixed spike 20.

In the embodiment of FIG. 8, the effect which turns and lifts thesleeve-mounted spike 15 is accomplished by placing a piece 14f of somematerial other than rubber inside the patterned element 12 which is tobe fitted with a spike, said piece being arranged to transmit the impactfrom the contact angle to the sleeve-mounted spike 15. A fixed spike 20may equally be used instead of the sleeve-mounted spike 15. In theembodiment of FIG. 8, a substantially rod-shaped body 14f e.g. ofplastic is inserted in the pattern element 12 which is meant to receivea spike, by cementing or in another way, said body resting with one endagainst the sleeve 19 of the sleeve-mounted spike 15, or against theflange 22 of the fixed spike 20, or against the rubber region 11substantially close thereto. The other end of this rod-shaped body 14fis located in the contact angle of the pattern element 12. Thedeformation of the rubber 11 is transmitted with the aid of therod-shaped body 14f e.g. to the flange 22 of the fixed spike 20, thusturning the fixed spike 20 to vertical position and also imparting tothe fixed spike 20 before road contact an upward acceleration, whichreduces the dynamic impact.

In the embodiment of FIG. 9, a body 14g has been installed inside thepattern element 12, which generates around itself in the rubber 11 astress field, indicated by C. Said stress field C meets the stressfield, indicated by B, which was produced at installation of thesleeve-mounted spike 15 or of the fixed spike 20, and turns the fixedspike 20 or the sleeve-mounted spike 15, to a more upright position thanthat seen in the figure. Such a stress field C also transmits thepressure resultant R₀ -R₁ produced at road contact of the patternelement 12 more rapidly e.g. to the flange 22 of the fixed spike 20,whereby the force component, described above, turning and lifting thefixed spike 20 or the sleeve-mounted spike 15, is produced.

Therefore, as noted above, the present invention is directed to avehicle tyre intended to be fitted with spikes, characterized in thatthe tyre 10 has asymmetric or non-homogeneous regions 14, 14a, 14b, 14c,14d, 14e, 14f, 14g disposed to produce a force component F₂ turning thefixed spike 20 or the sleeve-mounted spike 15 installed in the tyre 10,so that the fixed spike 20 or the sleeve-mounted spike 15 is arranged,at initial contact with the road surface 13, to meet the road surface 13in a substantially perpendicular position. At the same time, theasymmetric or nonhomogeneous region 14, 14a, 14b, 14c, 14d, 14e, 14f,14g of the tyre 10 is disposed to produce a force component F₁ liftingthe fixed spike 20 where the sleeve-mounted spike 15, whereby thevelocity at which the spike and the road meet, resulting from therotation of the tyre 10, is simultaneously arranged to be substantiallyreduced.

In the foregoing merely some of the advantageous embodiments of theinvention are presented, and it is clear to a person skilled in the artthat numerous modifications thereof can be contemplated within the scopeof the inventive concepts set forth above.

I claim:
 1. A vehicle tire fitted with at least one spike, said tire comprising at least one asymmetric or non homogeneous region disposed in said tire to generate a force component turning the spike fitted in the tire to meet a road surface in substantially perpendicular position at initial contact with the road surface, upon rotation of said tire.
 2. The combination of claim 1, wherein said region is positioned in said tire ahead of a location for receiving the spike, in a rotational direction of said tire.
 3. The combination of claim 1, wherein said tire is arranged to be fitted with a plurality of spikes and comprises a plurality of said regions, each said region being situated in said tire to generate said force component turning a respective spike upon the rotation of said tire.
 4. The combination of claim 1, wherein said region is provided by material of said tire being asymmetrically-shaped.
 5. The combination of claim 1, wherein said region is also positioned in said tire to generate a force component lifting the spike upon the rotation of the tire,whereby velocity at which the spike and road surface meet resulting from the rotation of the tire, is substantially reduced.
 6. The combination of claim 3, wherein said regions are constituted by eminences being provided on a wear surface of said tyre.
 7. The combination of claim 3, wherein said regions are constituted by pattern elements provided on a wear surface of said tire.
 8. The combination of claim 3, wherein said regions are constituted by knob configurations on a wear surface of said tire.
 9. The combination of claim 3, wherein said regions are constituted by configurations or portions running substantially in a longitudinal direction over a wear surface of said tire.
 10. The combination of claim 1, wherein said region is formed by treating tire material at a location of said region.
 11. The combination of claim 10, wherein said tire material has been hardened in said region location.
 12. The combination of claim 11, wherein said tire material has been hardened by applying at least one of heat, radiation, and chemicals.
 13. The combination of claim 11, wherein said hardened region is arranged adjacent to a hole in the tire for receiving the spike.
 14. The combination of claim 11, wherein about one-half of a wear surface of said tire of one side on a location for receiving the spike, has been hardened for directing a pressure effect upon the spike when situated at its receiving location and upon said tire rotation.
 15. The combination of claim 10, wherein said region is constituted by material different from material forming said tire being situated inside said tire and arranged to transmit impact from said tire with the road surface to the spike when said tire is rotated.
 16. The combination of claim 1, wherein said region is constituted by a body arranged in said tire to generate thereabout a stress field in material of said tire and which meets a stress field generated upon installation of the spike within said tire.
 17. The combination of claim 1, wherein the at least one spike is arranged in the tire to protrude therefrom. 